OK so I was writing a sentence to explain that there are three holes at the same angular position on a wheel (different radii).
I started to write; 'there are more than one hole at each angular position...' But... it sounds wrong. Don't you agree? 'There is more than one hole...' sounds much better.
The construction 'there is' or 'there are' is used to indicate existence of a single thing or a plurality of things (countable nouns) respectively.
In this case, it seems that the thing that you are indicating the existence of is whatever 'more' is referring to, not the 'one'. Which is, in this case, two holes (on top of the first, three in total). So why does it sound so bad?
If there were two holes in total, then sure, 'there is more than one' would make sense, since the 'more' is one hole.
Is there some kind of special rule in English to say that we always say 'there is more than one' because there is at least one more?
Otherwise, why would we say 'there is' when referring to a plural, countable noun like in the above example?